A bestseller in France, this mystery from Chattam (The Soul of Evil) is unlikely to repeat that success in the U.S. After stumbling across a political coverup, Marion, a clerical employee at a Paris morgue, takes refuge in remote Mont-Saint-Michel. There, while inventorying some books, Marion discovers bound within the covers of Poe's Narrative of A. Gordon Pym the diary of an English detective, Jeremy Matheson, describing his probe into a series of sadistic child murders in 1928 Cairo. Marion becomes obsessed with the diary and in finding the solution to the old case. Strangely, the third-person diary selections include the thoughts of characters who could not have conveyed them to Matheson. This oddity will raise the suspicions of astute readers, who will be less than shocked by the twist ending. In that subgenre featuring a modern character who seeks the truth about a past crime through study of a secret document, this effort comes up short.